Page end indicator mechanism for typewriters or like machines

ABSTRACT

A typewriter or similar machine provided with controls for automatically terminating the operations when the last line imprinted on a sheet is at least approximately at a given distance from the bottom edge of a sheet. A feeler coacts with the sheet to determine when the bottom edge of the sheet reaches a given location. At this moment a toothed wheel operates to store a given number of lines which are imprinted on the sheet subsequent to arrival of its bottom edge at this given location. After the toothed wheel receives this given number of lines, a line controlling pawl is automatically brought out of engagement with a ratchet wheel which is operatively connected to a platen thereby preventing further advance of the sheet. At the same time a blocking unit is automatically actuated to block the movement of the carriage of the machine.

United States Patent [191 Prade [451 Aug. 13, 1974 PAGE END INDICATOR MECHANISM FOR TYPEWRITERS OR LIKE MACHINES [75] Inventor: Wolfgang Prade, Nisou,

21 Appl. No.: 226,091

Related U.S. Application Data [63] Continuation-impart of Ser. No. 883,557, Dec. 9, 1969, abandoned, which is a continuation-in-part of Ser. No. 810,543, March 26, 1969, abandoned.

[30] Foreign Application Priority Data Mar. 28, 1968 Czechoslovakia 2379-68 [52] U.S. Cl. 197/189 [51] Int. Cl B4lj 29/44 [58] Field of Search 197/189, 193

[56] References Cited UNITED STATES PATENTS 1,053,922 2/1913 Neidig 197/189 1,053,923 2/1913 Ncidig..... 197/189 1,053,924 2/1913 Neidig 197/189 1,053,925 2/1913 Neidig 197/189 1,053,928 2/1913 Neidig 197/189 1,053,929 2/1913 Neidig 197/189 1,053,930 2/1913 Neidig 197/189 1,093,798 4/1914 Neidig 197/189 1,112,408 9/1914 Neidig 197/189 1,113,163 10/1914 Neidig 197/189 1,170,988 2/1916 Nibourel.....

1,656,428 1/1928 Deisch 197/189 1,685,314 9/1928 Davis 197/189 2,711,811 6/1955 Lambert 2,728,441 12/1955 Wendt 197/189 FOREIGN PATENTS OR APPLICATIONS 719,942 12/1954 Great Britain 197/193 Primary ExaminerErnest T. Wright, Jr. Attorney, Agent, or Firm-Arthur O. Klein [5 7 ABSTRACT A typewriter or similar machine provided with controls for automatically terminating the operations when the last line imprinted on a sheet is at least approximately at a given distance from the bottom edge of a sheet. A feeler coacts with the sheet to determine when the bottom edge of the sheet reaches a given location. At this moment a toothed wheel operates to store a given number of lines which are imprinted on the sheet subsequent to arrival of its bottom edge at this given location. After the toothed wheel receives this given number of lines, a line controlling pawl is automatically brought out of engagement with a ratchet wheel which is operatively connected to a platen thereby preventing further advance of the sheet. At the same time a blocking unit is automatically actuated to block the movement of the carriage of the machine.

4 Claims, 4 Drawing Figures CROSS-REFERENCE TO RELATED APPLICATION This application is a continuation-in-part of application Ser. No. 883,557 filed Dec. 9, 1969, now abandoned application Ser. No. 883,557 is a continuationin-part of application Serial No. 810,543, filed Mar. 26, 1969, now abandoned.

BACKGROUND OF THE INVENTION The present invention relates to machines, such as typing machines and the like, whereina sheet of paper has lines of information imprinted thereon one after the other with a given increment or spacing being provided from one line to the next.

In particular, the present invention relates to the problem of terminating the imprinting of the successive lines when the last line is at a given distance from the bottom edge of the sheet of paper.

As is well known, machines of this general type have a rotary platen on which the sheet of paper is located. After each line of information is imprinted the operator of the typing machine or the like actuates a structure which advances the sheet to the next line by turning the platen through a given angular increment. During operation of such a machine the bottom edge of the sheet is not visible, so that unless certain measures are taken the last line which is typed on the sheet will be located too close to the bottom edge of the sheet.

Naturally, it is possible for the operator of the machine to carefully watch for the time when sufficient lines have been imprinted on the sheet or to provide a sheet with a suitable light pencil mark which, when it becomes visible, will indicate to the operator that the typing should be terminated. However, the disadvantage of this type of operation is that it requires the attention of the operator and results not only in taking attention away from more important areas but also in forgetfulness so that when the operator is distracted-the typing or imprinting will continue until the last line is located too close to the bottom edge of the sheet.

There are, of course, many different types of known devices which seek to solve this problem by providing the operator with a signal of some sort to indicate when the operations should be terminated on a given sheet. While the known devices for this purpose operate with more or less success, thay all suffer from the drawback of being relatively complex and in many cases these devices require paper of given thickness as well as structure requiring a large space at the region of the typing machine.

Many of the known devices provided for this purpose have the disadvantage of operating in dependence upon the length of the sheet or the number of lines which have already been imprinted. These devices count all of the lines which have previously been imprinted and are incapable of operating properly when the first line is placed on the sheet at a distance which is spaced from the top edge of the sheet by an amount greater than a predetermined amount. Also, devices of this type will not operate properly when, as very frequently happens, the operator of the typing machine repeatedly returns to previously typed lines on the sheet in order to correct errors.

Furthermore, there are some known devices, of this type, which count the lines in the manner indicated above, and are in the form of units mounted in a highly disadvantageous manner on the frame of the machine where they occupy far too much space and also where the thus-mounted unit must coact through a suitable transmission with the movable carriage of the machine.

Moreover, one of the most significant disadvantages of the known devices resides in the fact that, upon reaching the last line which is to be imprinted on a given sheet, these known devices provide only a signal, such as an audible signal in the form of the ringing of a bell, for example, without, however, preventing further advance of the sheet and typing of further lines thereon. Such signals have not only the disadvantage of easily being unnoticed by the operator, but also they require unavoidably an undesirably great part of the attention of the operator who remains tense while expecting the signal so that with devices of this type the operator will very rapidly become fatigued.

SUMMARY OF THE INVENTION It is accordingly a primary object of the present invention to provide a structure which will avoid all of the above drawbacks.

In particular, it is an object of the present invention to provide a typewriter, or similar machine for imprinting lines of information on a sheet of paper, with a structure which will automatically terminate the imprinting of lines on the sheet, when the last line is located at a given distance from the bottom edge of the sheet of paper, without requiring any attention on the part of the operator.

In addition, it is an object of the invention to provide a structure of this type which will occupy only a small amount of space and which can easily be incorporated into existing machines without any radical reconstruction.

It is also an object of the invention to provide a construction which will automatically terminate imprinting of lines on a sheet, when the last imprinted line is at a given distance from the bottom edge of the sheet of paper, irrespective of the location of the first line on the sheet and irrespective of the number of lines that the operator has returned to previously typed lines, in order to correct errors, for example.

It is also an object of the present invention to provide a device of this type which can be readily adjusted so as to determine the location of the last imprinted line, at least approximately, with respect to the bottom edge of the sheet of paper.

Yet another object of the invention is to provide a construction of this type which is relatively simple and inexpensive, which will not in any way influence the normal operation of the machine, and which does not require any particular manipulations by the operator in order to bring about the proper functioning of the device of the invention.

Moreover, it is an object of the invention to provide a construction which has an operation which does not depend upon the thickness of the paper and which does not provide any audible or visible signal, or the like, which requires the attention of the operator.

Another object of the invention is to provide a construction of this type which will not only prevent further advancing of a sheet of paper after the last line has been imprinted thereon but which also will prevent further movement of the carriage of the machine.

However, it is also an object of the present invention to provide a device of this type which can easily be released so that the parts can return to their initial position in connection with the introduction of a new sheet of paper and the removal of the already imprinted sheet of paper from the machine.

In particular, it is an object of the invention to provide a device of this type which will in no way interfere with the introduction of a sheet of paper into the machine.

In accordance with the invention the machine has the usual support means for supporting the sheet on which the lines are to be printed one after the other as well as a conventional advancing means for advancing the sheet of paper from one line to the next. With the structure of the invention there is a detecting means which detects when the bottom edge of the sheet of paper reaches a predetermined location. When the detecting means thus detects the arrival of the bottom edge of the sheet of paper at this location, a blocking means of the invention automatically responds to bring about, after imprinting of a given number of lines, blocking of the advancing means so that additional lines cannot be imprinted on the sheet of paper by feeding of the paper by a line controlling pawl.

BRIEF DESCRIPTION OF DRAWING The invention is illustrated by way of example in the accompanying drawing which forms part of this application and in which:

FIG. 1 is a schematic representation of a sheet of paper on which lines of information are imprinted, showing various dimensions which are important to a full understanding of the invention;

FIG. 2 is a fragmentary perspective illustration of details of a machine which has the structure of the invention, parts of the structure of FIG. 2 also being indicated schematically;

FIG. 3 is a schematic illustration of the operation of the feeler; and

FIG. 4 is a detailed illustration of the adjustable stop.

DESCRIPTION OF A PREFERRED EMBODIMENT A sheet of paper 40 on which lines of information are to be successively imprinted, as by being typed thereon, is to be provided with a given number of lines situated at a given distance from each other. Thus, FIG. 1 indicates the distance M from one line to the next. Between the first line 411 and the top edge 41 of the sheet 40 there is an initial given distance A where there will be no imprinting of any information. In the same way, between the last line 429 and the bottom edge 42 of the sheet of paper 40 there will be a distance D where there will be no imprinting of any information. The next-to-last line 428 is located at a distance C from the bottom edge 42 of the sheet of paper 40 while the next upper line 427 is situated at a distance B from the bottom edge 42 of the sheet of paper 40. The sheet of paper 40 has a total height V. The beginning and end of each line of information are brought about in a wellknown manner by the adjustment of suitable stops, margin tabs or the like, as is well known, these features forming no part of the present invention.

At the carriage 20 there is a rotary platen 210 with the shaft 2101 of the rotary platen 210 being supported together with the rotary platen 210 for rotary movement on the carriage 20. On the very same shaft 2101 there is mounted the ratchet 211, which may be considered fixed to the shaft 2101 so as to rotate the latter together with the rotary platen 210 when the ratchet 211 turns, although this ratchet 21.1 in the actual construction is releasably coupled with the shaft 2101 through a suitable release clutch well-known in the art and not forming part of the present invention so that it is not illustrated. There is also mounted on the shaft 2101 a toothed wheel 212 which is freely turnable on the shaft 2101. The ratchet 211 and toothed wheel 212 are respectively provided with teeth 2111 and 2121, but the teeth 2121 of the toothed wheel 212 extend only along a part of the periphery of the latter. At the remainder of the periphery of the toothed wheel 212 there is a camming peripheral portion 2122 which extends outwardly beyond the teeth 2121 and which has a leading curved surface 2122a. This camming peripheral portion 2122 also has a stop surface 2122b.

A spring means coacts with the toothed wheel 212 in order to urge the latter to-a given starting position, and this spring means includes a return spring 291 mounted on a rotary return pinion 290 which meshes with the toothed wheel 212 and which is carried by a pin 29 which is carried by the carriage 20. The return spring 291 acts upon the return pinion 290 so as to transmit to the latter a torque which is also transmitted to the toothed wheel 212 to urge the latter resiliently and yieldably back toward a given starting position, the I force of the return spring 291 acting in the direction indicated by the curved arrow on toothed wheel 212 in FIG. 2. In this given starting position the stop surface 2122b of the camming peripheral portion 2122 remains on an adjustable stop 220 (FIG. 4). The adjustable stop 220 can be moved in both directions as indicated by a double arrow. According to F IG. 4 the adjustable stop 220 is slidably mounted in a carriage portion 201. On the lower side of the stop 220 there are three spaced recesses 221.

A ball 222 is selectively urged into one of these recesses 221 by virtue of a spring 223. A manipulation rod 224 is fixed to the stop 220.

In addition to meshing of the teeth 2121 of the toothed wheel 212 with the return pinion 290, these teeth 2121 also receive the pawl 2701 of a swingable lever 270 (FIG. 2) supported for swinging movement on a pin 27 carried by the carriage 20 and having a free bottom end forming the pawl 2701 which is received in the teeth 2121 to prevent return of the toothed wheel 212 by the return spring 291 to its starting position.

The swingable lever 270 has, above the pivotal mounting pin 27 therefor, a second arm 2702 which terminates at its top end in a manually engagable button 2705 or the like. This upper arm 2702 of the swingable lever 270 carries a pin 2703 which serves to pivotally connect to the manually swingable lever 270 a motion-transmitting member 271 which can swing with respect to the swingable lever 270 at the pin 2703 thereof. Moreover, a spring 2704 acts on the swingable lever 270 to urge the pawl 2701 thereof into engagement with the teeth 2121 of the toothed wheel 212.

Thus, the motion-transmitting member 271 has the form of a one-armed lever, and this motiontransmitting member 271 forms a device for automatically transmitting to the swingable lever 270 a movement which releases the toothed wheel 212 for return to its starting position, except under certain conditions referred to below. For this purpose the motiontransmitting member 271 has a downwardly directed projection 2711 which is pulled towards the feeler 205 by means of a spring 2713 and a second, rearwardly directed projection 2712 which is distant from the manually operable swingable lever 270. Both of these projections 2711 and 2712 form mechanical couplings, the projection 2711 coacting with a gongue 2051 on the swingable feeler 205 while the projection 2712 coacts with a control portion 2402 projecting from a shifting means 240.

The feeler 205 illustrated in FIGS. 2 and 3 has upper arm portions provided with eyes 2058 through which an elongated rod 22 of the carriage extends so that in this way the feeler 205 is supported for swinging movement on the rod 22. This feeler 205 forms essentially a one-armed lever. Actually, as is apparent from FIG. 2, there are a number of these one-armed levers interconnected with each other for swinging movement as a unit. These levers terminate in feeler portions 2055.

The feeler 205 has a tongue 2051 which engages the projection 2711 of the motion-transmitting member 271. Also, the feeler 205 has atits left end, as viewed in FIG. 2, a projection 2057 the outer end of which coacts with the shifting means 240. Thus, the shifting means 240 carries an abutment 2407 which engages the projection 2057 when the shifting means 240 is in its resting position to maintain the feeler 205 in a given rest position in opposition to the action of a spring 2053, and in this position, determined by the coacting of the abutment 2407 and the projection 2057, the feeler 205 is located where it will not interfere with the movement of paper into the machine.

The shifting means 240 is guided for movement by way of suitable guides 24 carried by the carriage 20, and the shifting of the shifting means 240 forwardly and rearwardly along the guides 24 of the carriage 20 brings about the movement of the shifting means 240 in working stroke Y and return stroke X (See FIG. 2). It is this shifting means 240 which swingably carries a linecontrolling pawl 241 which coacts with the teeth 2111 of the ratchet 211 as well as with the teeth 2121 of the toothed wheel 212. Thus, when displaced rearwardly along the working stroke Y, the shifting means 240 would cause the line-controlling pawl 241 to bring about turning movement of the ratchet 211 and toothed wheel 212 through a predetermined angular increment. In this way the support means for the paper 40, formed by the rotary platen 210, is also turned through this particular angular increment.

The return movement of the shifting means 240 is brought about automatically by way of a return spring 245. This shifting means 240 is actuated in a known way by way of a line-advancing control lever 230 which is swingably mounted on the carriage 20 by way of a pivot pin 23 which is carried by the carriage 20. The swing of the line-advancing control lever 230 actuated by the operator is transmitted to the shifting means 240 carrying swingable line-controlling pawl 241 through a roller 231 rotatably carried by the fragmentarily illustrated manually swingable line-advancing control lever 230 and bearing against a front end of the shifting means 240. The swingable line-advancing control lever 230 is returned to its starting position in a known way by an unillustrated spring.

The line-controlling pawl 241 is supported for swinging movement on the shifting means 240 by way of a pivot pin 2411 on which the line-controlling pawl 241 is freely swingable, a spring 2413 acting on the line controlling pawl 241 to urge the pawl 24] simultaneously into engagement with the teeth 2111, 2121 of the ratchet 211 and toothed wheel 212, respectively.

Moreover, the line-controlling pawl 241 is provided with a blocking projection 2412 which brings about actuation of and forms part of the blocking means of the invention referred to in greater detail below. It is this blocking projection 2412 which brings about the movement of the blocking lever 280 of a train of motiontransmitting elements which produce blocking of the movement of the carriage 20 as described below. This blocking lever 280 is described in greater detail below.

At the rear end of the shifting means 240 is located the projecting control portion 2402 which is located at the elevation of the rear projection 2712 of the motiontransmitting member 271 when the projection 2711 rests on the tongue 2051 of the feeler 205. Moreover, the shifting means 240 has the above-described abutment 2407 which coacts with the projection 2057 to provide a mechanical coupling between the shifting means 240 and the feeler 205.

The blocking lever 280 is supported in such a way by a pin 28 fixed to the carriage 20 that it is capable not only of swinging in a horizontal plane but also is capable of swinging to some extent in a vertical plane to bring about an over-springing swinging movement, which permits the blocking projection 2412 of the linecontrolling pawl 241 to move beneath the blocking lever 280 during the return stroke X of the shifting means 240. A fixed stop 28a carried by the carriage 20 assures, during this return stroke X, that the blocking lever 280 will be returned to its predetermined rest position by a spring (not shown) acting upon lever 282. This blocking lever 280 is furthermore pivotally connected with a motion-transmitting rod 281 which is in turn connected to the next element in the form of a lever 282. This lever 282 is fixed to and projects radially from a rotary blocking rod 283 supported for rotary movement about its axis in suitable bearings of the carriage 20. This rotary blocking rod 283 finally is connected with a blocking pawl 284 which is capable of being received between two adjacent teeth 111 of a stationary comb 11 fixed to and carried by the frame 10 of the machine.

The sheet of paper 40 is guided before its entrance beneath the rotary platen 210 and during its movement around the rotary platen 210 by a two-part sheet metal guide composed of an upper component 21a and a lower component 21b. A gap 210 is defined between these components 21a and 21b. The upper component 21a and the lower component 21b are formed with cutouts 2102 which make it possible for the feeler portions 2055 of the feeler 205 to swing during movement of the feeler 205 in a manner described below. These components 21a and 21b are also carried by the carriage 20.

Over the rotary platen 210 there is located, in a wellknown manner, a swingable support plate 200 for the sheet of paper 40, this support plate 200 also being carried for swinging movement, together with the feeler 7 205, by the elongated horizontally extending transverse rod 22 which is carried by the carriage 20.

Referring now to the drawing, the manner in which the structure functions is as follows:

After the sheet of paper 40 has been intially introduced into the machine and the first line 411 has been located at the selected distance from the top edge 41 of the sheet of paper 40, this first line 411 is imprinted. Then the line-advancing control lever 230 is swing through the operating stroke Y to bring about the movement of the shifting means 240 through the working stroke Y thereof. During this movement the linecontrolling pawl 241 rotates the ratchet 211 as well as the toothed wheel 212 through the same angular increment, which corresponds to the angular increment through which the rotary platen 210 is turned. Thus, this rotary platen 210 is coupled to the ratchet 211 for turning movement therewith at least during advancing of the shifting means 240 rearwardly along its working stroke Y. The turning of the toothed wheel 212 through the predetermined increment takes place in opposition to the force of the return spring 291 which acts on the return pinion 290, and the pawl 2701 of the manually releasable swingable lever 270 coacts with the teeth 2121 of the toothed wheel 212 to maintain the latter in the position to which it has been turned by the linecontrolling pawl 241.

Directly thereafter the release of line-advancing control lever 230 brings about automatic return of the lineadvancing control lever 230 through its return stroke X, under the influence of an unillustrated spring so that the line-advancing control lever 230 returns to its starting position. At the same time, the shifting means 240 is returned along the return stroke X back to its starting position by the spring 245. The projection 2057 is engaged by the abutment 2407 and this causes-the movement of the feeler 205 to its starting position, allowing this introduction of the sheet of paper 40 into the machine. The projecting control portion 2402 at the rear end of the shifting means 240 will engage the rearwardly directed projection 2712 of the motiontransmitting member 271 which is swingably connected to the swingable lever 270 so as to swing the latter about the pin 27 in opposition to the spring 2704 so as to displace the pawl 2701 out of engagement with the teeth 2121 of the toothed wheel 212. Since at the end of the return stroke X of the shifting means 240 the line-controlling pawl 241 is out of engagement with the teeth 2111 and 2121 of the ratchet 211 and toothed wheel 212, respectively, the return pinion 290 is capable of transmitting the force of the return spring 291 to the toothed wheel 212 to turn the latter back until the stop surface 2122b of the camming peripheral portion 2122 has again engaged the adjustable stop 220 which determines the starting position of the toothed wheel 212. It is to be noted that at the moment when the rearwardly directed projection 2712 is positioned at the level of the projection control portion 2402 the return movement of the feeler 205 has not yet taken place. Thus, at each return stroke X of the shifting means 240, the toothed wheel 212 returns to its starting position, assuming, of course that at every return stroke X the manually operable swingable lever 270 is turned by the motion-transmitting member 27] in the manner dcscribed.

This latter requirement is fulfilled, however, only as long as the sheet of paper 40 prevents the feeler portions 2055 of the feeler 205 from entering into the cutouts 2102 of the components 21a and 21b of the twopart metal guide sheet. If, however, the bottom edge 42 of the sheet of paper 40 has already reached the location of the gap 210, so that the cutouts 2102 are no longer covered by the sheet of paper 40, then the spring 2053 as well as the gravitational action resulting from the weight of the feeler 205 will result in downward movement of the latter to its lower limiting position. This downward movement of the feeler 205 and its feeler portions 2055 can be effected during the working stroke Y of the shifting means 240, i.e., when the abutment 2407 is out of engagement with the projection 2057, of the feeler 205. Of course, the tongue 2051 will necessarily move upwardly (see FIG. 3) and thus the downwardly directed projection 2711 of the motion-transmitting member 271 will move upwardly with counterclockwise upward swinging of the motiontransmitting member 271. The result is that the rearwardly directed projection 2712 is now located above the projecting ,contro] portion 2402 of the shifting means 240. When the shifting means 240 is returned by the return stroke X to its rest position, the control portion 2402 is out of engagement with the motiontransmitting member 271. Thus the abutment 2407 will coact with the projection 2057, so that the feeler 205 will raise out of the path of movement of the paper 40. The tongue 2051 moves downwardly, but the downward movement of the motion-transmitting member 271 is hindered by the control portion 2402 lying under it.

The result is that the rearwardly directed projection 2712 is now located beyond the operational range of projecting control portion 2402 of the shifting means 240. As a result the swingable lever 270 is no longer influenced by the return movement of the shifting means 240 and the pawl 2701 thereof remains in engagement with the teeth 2121 in the toothed wheel 212. Therefore, the angular turning of the toothed wheel 212 through a distance corresponding to the shifting of the sheet of paper 40 from one line to the next is retained in the toothed wheel 212 and during advance of the sheet of paper 40 through the distance M in preparation for the imprinting of the next line, the next following increment is also retained in the toothed wheel 212. Thus the toothed wheel 212 will be angularly turned through a number of angular increments corresponding to the distance M from one line 427 to the next line 428, for example. Thus, the line-controlling pawl 241 will, during each working stroke Y of the shifting means 240, now operate to bring about a series of stepped rotational movements of the toothed wheel 212 until the leading curved surface 2122a of the camming peripheral portion 2122 of the toothed wheel 212 engages the line-controlling pawl 241. The riding of the line-controlling pawl 241 onto the camming surface portion 2122 will result in raising of the line-controlling pawl 241 with passing of the line-controlling pawl 241 finally beneath the blocking lever 280 in preparation for engagement of the blocking projection 2412 of the line-controlling pawl 24] with the blocking lever 280 during the next working stroke Y of the shifting means 240. This raising of the line-controlling pawl 241 out of operative engagement with the ratchet 211 and toothed wheel 212 prevents any further actuation of these components and thus prevents any further turning of the rotary platen 210 by way of actuation of the lineadvancing control lever 230.

This raising of the line-controlling pawl 241 will thus cause its blocking projection 2412 to engage and swing the blocking lever 280 when an attempt is made to advance the shifting means 240 rearwardly along its working stroke Y, the starting position of the blocking lever 280 being determined in the manner described above by the fixed stop 28a. The engagement of the blocking projection 2412 of the line-controlling pawl 241 with the blocking lever 280 will turn the latter in a horizontal plane so as to produce a forward pulling of the motion-transmitting rod 281 and a counterclockwise turning of the lever 282 together with the blocking rod 283, as viewed in FIG. 2. This rotary swinging of the blocking rod 283 will result also in counterclockwise, downward swinging of the blocking pawl 284 whose end is received in the gap between two adjacent teeth 111 of the stationary comb 11 fixed to the frame 10. In this way any furthermovement of the carriage 20 will be blocked. Lever 280 is returned to its starting position by the action of a spring (not shown) which acts upon lever 282.

The sheet of paper 40 which has now had the last line 429 imprinted thereon is removed in the usual manner out of the machine by manual turning of the rotary platen 210 directly through a suitable known hand wheel, without any actuation of the line-changing mechanism. Thus, the structure of the invention permits the rotary platen 210 to be manually turned directly by the operator without any actuation of the structure which advances the sheet of paper 40 from one line to the next. The blocking of the line advancing structure and carriage 20 movement is eliminated simply by manual engagement of the button 2705 at the top end of the manually operable release swingable lever 270. This release swingable lever 270 is manually turned at this time through a distance sufficient to displace the bottom pawl 2701 out of engagement with the teeth 2121 of the toothed wheel 212. The return pinion 290 will now be acted upon by the return spring 291 so as to return the toothed wheel 212 automatically to its starting position where the stop surface 2122b engages the adjustable stop 220. In this way the entire machanism is again in a position ready to receive the next sheet of paper 40 and repeat the above operations since even the manually operable swingable lever 270, after the operator releases the button 2705, will be returned by the action of the spring 2704 into its initial position where the buttom pawl 2701 thereof will engage the teeth 2121 of the toothed wheel 212. At the same time the motion-transmitting member 271 will be returned by the action of gravity or by spring 2713 into its initial position.

The adjustable stop 220 can be moved manually with the manipulation rod 224 in both directions as indicated by a double arrow in FIG. 4. Thus the leading curved surface 2122a will be moved away from or closer to the line-controlling pawl 241. The distance between the leading curved surface 2122a and the linecontrolling pawl 241 is directly proportional to the distance D, i.e., to the distance between the last line 429 and the bottom edge 42 of the sheet of paper 40. The practical value of this distance D is about 2 to cm.

The above-described structure of the invention operates reliably and with a precision which is sufficient for the usual machine operations. For the sake of completeness it should be noted that there is a certain negligible inaccuracy in the structure. Thus, the distance A between the first line 411 and the top edge 41 of the sheet of paper 40 is not influenced in any way so that it can be set at any desired magnitude. Therefore, the instant when the repeated returning of the toothed wheel 212 into its initial position terminates is determined by that particular location of the sheet of paper 40 when the bottom edge 42 thereof has uncovered the cutouts 2101 in the sheet metal upper component 21a and lower component 21b. This particular position is not determined by the distance of any particular line such as line 427, for example, from the cutouts 2101, which is to say from the gap 21c. Instead it is possible to have for this determination a tolerance which at a maximum corresponds to the distance M from one line to the next. Of course, in order to have the possibility of such a maximum tolerance it is essential that each sheet of paper 40 be capable of having any arbitrarily determined distance A from its top edge 41 to the first line 411. If, however, this particular distance A is predetermined by any suitable means, so that all of the successive sheets of paper 40 will have the same distance A from the edge 41 to the first line 411, then even this particular tolerance will disappear and the distance D will be the same on all of the sheets of paper 40.

A means suitable for this purpose can, for example, take the form of a known index situated over the location where the type members (one is shown in 30 in FIG. 2) engage the sheet of paper 40, or, after the sheet of paper 40 has been introduced until its top edge 41 is at the elevation of a scale (not shown), by way of the line-advancing control lever 230 it is possible to count a few lines so that the rotary platen 210 together with the sheet of paper 40 are turned through a few lines corresponding to a predetermined angle, whereupon the typing of the first line is begun. Even with this actuation of the line-advancing control lever 230 there will be a stepwise turning of the toothed wheel 212 which, however, is returned to its starting position upon each return stroke of the shifting means 240 since the sheet of paper 40, as described above, will assure release of the pawl 2701 of the manually releasable swingable lever 270 so that the reverse turning of the toothed wheel 212 is assured.

As has been indicated above, a considerable number of advantages are provided with the structure of the invention. Among these advantages are the following:

I. The device of the invention can be built into existing machines without any particularly great modification thereof.

2. The device of the invention does not in any way undesirably influence the operation of the machine and does not undesirably affect either the movement of the type levers 30 or the carriage 20, and also there is no undesirable influence on the turning platen.

3. The device of the invention as well as the operation thereof is extremely simple and requires no manipulations by the operator.

4. The operation of the device of the invention does not depend in any way upon the thickness of the paper 40.

5. The device of the invention does not require the actuation of any signal, such as an acoustic signal.

6. The device of the invention will automatically block, after imprinting of the last line 429, not only further feeding of the paper 40 by the line controlling pawl 241 but also further movement of the carriage 20.

7. The release of the device is brought about by way of a simple movement, and after the release the parts automatically return to their starting position in which they are again set to operate reliably.

8. The device of the invention does not in any way influence or render more difficult the introduction of paper 40 into the machine. Duringintroduction of a sheet of paper 40 into the machine the line-controlling components remain in their starting positions out of the path of movement of the introduced sheet of paper 40 to eliminate all hindrance to the introduction of it. Even the feeler 205 is maintained out of the path of movement of the sheet of paper 40 by way of the coacting of the abutment 2407 with the projection 2057, as described above.

9. With every introduction of a new sheet of paper 40 and a subsequent setting of the machine to type or imprint the lines of information thereupon, the previous angular position of the toothed wheel 212 is zeroed.

10. It is possible with the structure of the invention to return from any given line up to a previously imprinted line, for the sake of correcting typing errors, for example, without in this way influencing or changing the initial setting of the machine.

11. It is possible to very easily adjust the distance from the last imprinted line 429 to the bottom edge 42 of the sheet of paper 40.

Although the invention is illustrated and described with reference to a single preferred embodiment thereof, it is to be expressly understood that it is in no way limited to the disclosure of such a preferred embodiment but is capable of numerous modifications within the scope of the appended claims.

What is claimed is:

1. In a machine, such as a typewriter or the like, having a frame, a carriage slidably mounted on the frame of the machine, means for imprinting horizontal lines of information one after the other, said horizontal lines of information approaching the bottom edge of a sheet of paper mounted on the carriage of the machine,

a rotary platen mounted on the carriage for supporting said sheet of paper during the imprinting of the horizontal lines of information thereon,

a ratchet wheel fixedly mounted on the rotary platen for advancing the rotary platen line-by-line, and

a manually operable line advancing control lever swingably mounted on the carriage,

the improvement which comprises;

a page end indicator and stop mechanism, said mechanism comprising a toothed wheel mounted near and coaxially of the ratchet wheel and having a loose running fit therewith, the toothed wheel having a given starting position, the toothed wheel having a camming peripheral portion exceeding the ratchet wheel in radial height, the camming peripheral portion of the toothed wheel having a leading curved surface and a stop surface,

a stop mounted on the carriage in position to be engaged with the stop surface of the toothed wheel at said given starting position of the toothed wheel,

spring means coacting with the toothed wheel for urging the toothed wheel to said given starting position,

shifting means slidably guided in the carriage, said shifting means coacting with said manually operable line advancing control lever, said shifting means having a spring and a predetermined rest position, said shifting means carrying an abutment and a control portion, said shifting means being constantly urged to said predetermined rest position by said spring,

a line controlling pawl swingably mounted on the shifting means and constantly urged by a spring toward a position in which the line controlling pawl meshes with both said ratchet and toothed wheels,

the line controlling pawl moving the ratchet and toothed wheels during operation of the shifting means,

a swingable spring urged lever having means for preventing return of the toothed wheel to the said starting position, said swingable spring urged lever carrying a selectively operable motion transmitting member, mounted between the swingable spring urged lever and the control portion of the shifting means, whereby each operation of the shifting means is transmitted so as to disengage the means for preventing return of the toothed wheel from the toothed wheel, whereby the spring means returns the toothed wheel to the given starting position, and

a feeler swingably mounted on the carriage having a spring constantly urging the feeler toward the abutment of the shifting means, said feeler having at least one movable paper engaging feeler portion,

said feeler having a tongue cooperating with the motion transmitting member to disable operation of the motion transmitting member by the shifting means when the paper has been fed into a predetermined terminal position by the line controlling pawl, thereby to prevent further feeding of the sheet of paper by the line controlling pawl.

2. A machine according to claim 1, comprising a paper guide carried by the carriage, the guide having at least one cutout for receiving the feeler portion after the bottom edge of the sheet of paper has passed over the cutout whereby the tongue of the feeler then rises, the feeler and the motion transmitting member having selectively engageable respective parts, which move with the feeler and the motion transmitting member, whereby rising of the tongue of the feeler raises the motion transmitting member out of engagement with the control portion of the shifting means, the means for preventing return of the toothed wheel remaining engaged with the toothed wheel and the toothed wheel being rotated with the ratchet wheel by the line controlling pawl until the camming peripheral portion on said toothed wheel is positioned to disengage the line controlling pawl from said ratchet wheel during succeeding operations of said shifting means, thereby preventing the rotation of the ratchet wheel and further feeding of the sheet of paper by the line controlling pawl.

3. A machine according to claim 1, comprising a blocking lever swingably mounted on the carriage,

a comb mounted on the frame of the machine,

a blocking pawl swingably mounted on the carriage for controlled engagement with the comb, said blocking pawl being coupled with the blocking lever, and

for the toothed wheel is adjustable and is slidably mounted on the carriage, the adjustable stop having recesses, a ball urged by a spring into one of the recesses, and means fixed to the adjustable stop for sliding the adjustable stop on the carriage whereby the extent of the last imprinted line of information from the bottom edge of the sheet of paper may be varied. 

1. In a machine, such as a typewriter or the like, having a frame, a carriage slidably mounted on the frame of the machine, means for imprinting horizontal lines of information one after the other, said horizontal lines of information approaching the bottom edge of a sheet of paper mounted on the carriage of the machine, a rotary platen mounted on the carriage for supporting said sheet of paper during the imprinting of the horizontal lines of information thereon, a ratchet wheel fixedly mounted on the rotary platen for advancing the rotary platen line-by-line, and a manually operable line advancing control lever swingably mounted on the carriage, the improvement which comprises; a page end indicator and stop mechanism, said mechanism comprising a toothed wheel mounted near and coaxially of the ratchet wheel and having a loose running fit therewith, the toothed wheel having a given starting position, the toothed wheel having a camming peripheral portion exceeding the ratchet wheel in radial height, the camming peripheral portion of the toothed wheel having a leading curved surface and a stop surface, a stop mounted on the carriage in position to be engaged with the stop surface of the toothed wheel at said given starting position of the toothed wheel, spring means coacting with the toothed wheel for urging the toothed wheel to said given starting position, shifting means slidably guided in the carriage, said shifting means coacting with said manually operable line advancing control lever, said shifting means having a spring and a predetermined rest position, said shifting means carrying an abutment and a control portion, said shifting means being constantly urged to said predetermined rest position by said spring, a line controlling pawl swingably mounted on the shifting means and constantly urged by a spring toward a position in which the line controlling pawl meshes with both said ratchet and toothed wheels, the line controlling pawl moving the ratchet and toothed wheels during operation of the shifting means, a swingable spring urged leveR having means for preventing return of the toothed wheel to the said starting position, said swingable spring urged lever carrying a selectively operable motion transmitting member, mounted between the swingable spring urged lever and the control portion of the shifting means, whereby each operation of the shifting means is transmitted so as to disengage the means for preventing return of the toothed wheel from the toothed wheel, whereby the spring means returns the toothed wheel to the given starting position, and a feeler swingably mounted on the carriage having a spring constantly urging the feeler toward the abutment of the shifting means, said feeler having at least one movable paper engaging feeler portion, said feeler having a tongue cooperating with the motion transmitting member to disable operation of the motion transmitting member by the shifting means when the paper has been fed into a predetermined terminal position by the line controlling pawl, thereby to prevent further feeding of the sheet of paper by the line controlling pawl.
 2. A machine according to claim 1, comprising a paper guide carried by the carriage, the guide having at least one cutout for receiving the feeler portion after the bottom edge of the sheet of paper has passed over the cutout whereby the tongue of the feeler then rises, the feeler and the motion transmitting member having selectively engageable respective parts, which move with the feeler and the motion transmitting member, whereby rising of the tongue of the feeler raises the motion transmitting member out of engagement with the control portion of the shifting means, the means for preventing return of the toothed wheel remaining engaged with the toothed wheel and the toothed wheel being rotated with the ratchet wheel by the line controlling pawl until the camming peripheral portion on said toothed wheel is positioned to disengage the line controlling pawl from said ratchet wheel during succeeding operations of said shifting means, thereby preventing the rotation of the ratchet wheel and further feeding of the sheet of paper by the line controlling pawl.
 3. A machine according to claim 1, comprising a blocking lever swingably mounted on the carriage, a comb mounted on the frame of the machine, a blocking pawl swingably mounted on the carriage for controlled engagement with the comb, said blocking pawl being coupled with the blocking lever, and a blocking projection on the line controlling pawl, said blocking projection being engageable with the blocking lever after the line controlling pawl is carried out of mesh with the ratchet wheel by the camming peripheral portion of the toothed wheel, whereby any further turning of the rotary platen is blocked.
 4. A machine according to claim 1, wherein the stop for the toothed wheel is adjustable and is slidably mounted on the carriage, the adjustable stop having recesses, a ball urged by a spring into one of the recesses, and means fixed to the adjustable stop for sliding the adjustable stop on the carriage whereby the extent of the last imprinted line of information from the bottom edge of the sheet of paper may be varied. 